canirequire

canirequire › ESM-only › is-docker

Is is-docker ESM-only? Can you require() it?

Check if the process is running inside a Docker container

Last verified Sep 9, 2026 against is-docker@4.0.0. JSON

ESM-only ESM-only since 3.0.0 — last CommonJS version is 2.2.1

is-docker dropped its CommonJS build in 3.0.0 (August 2021). The last version you can require() on every Node.js version, including 18 and older, is 2.2.1, published Apr 9, 2021.

On Node.js 20.19+, 22.12+ and every newer release, require("is-docker") works anyway: Node can load synchronous ES modules through require(). Verified on Node 20, 22, 24, 26. Node.js 18 and older still fail with ERR_REQUIRE_ESM.

is-docker@4.0.0 declares engines ">=20", so Node.js 18 is outside its supported range regardless of module format.

Latest
4.0.0 (Sep 15, 2025)
Module format
ESM-only
Last CommonJS version
2.2.1
ESM-only since
3.0.0 (Aug 31, 2021)
TypeScript types
Bundled
Node engines
>=20
Weekly downloads
110.0M
License
MIT

Does is-docker@4.0.0 actually load? Runtime test results

Installed and executed on Sep 9, 2026 with require("is-docker") from a CommonJS file and import "is-docker" from an ES module.

Runtimerequire("is-docker")import "is-docker"
Node.js 18✗ failsERR_REQUIRE_ESM✓ works
Node.js 20✓ works✓ works
Node.js 22✓ works✓ works
Node.js 24✓ works✓ works
Node.js 26✓ works✓ works
Bun 1.4✓ works✓ works

How to import is-docker

ES modules (import)

import isDocker from "is-docker";

CommonJS (require)

// Node.js 20.19+ / 22.12+ / newer (package has no top-level await):
const isDocker = require("is-docker");

// Any Node.js version:
const isDocker = await import("is-docker");

// Or pin the last CommonJS release:
// npm install is-docker@2.2.1

Module format by version

Derived from the type, main and exports fields of every stable release on npm (10 versions; the newest 10 shown).

VersionsFormatFirst published
3.0.0 – 4.0.0ESM-onlyAug 31, 2021
1.0.0 – 2.2.1CommonJSApr 8, 2015

Frequently asked

Is is-docker ESM-only?

is-docker@4.0.0 is ESM-only. is-docker dropped its CommonJS build in 3.0.0 (August 2021). The last version you can require() on every Node.js version, including 18 and older, is 2.2.1, published Apr 9, 2021.

Which version of is-docker still supports CommonJS / require()?

2.2.1 is the last version of is-docker with a CommonJS build. Install it with "npm install is-docker@2.2.1". Every version from 3.0.0 on is ESM-only.

How do I use is-docker from a CommonJS file?

Use a dynamic import: const mod = await import("is-docker"). On Node.js 20.19+, 22.12+ and newer, a plain require("is-docker") also works for ESM packages that do not use top-level await. Alternatively pin is-docker@2.2.1.

Does is-docker work in Bun?

Yes. import "is-docker" loaded successfully in Bun 1.4 on Sep 9, 2026.

Does is-docker ship TypeScript types?

Yes. is-docker bundles its own type declarations; no @types package is needed.

Links

Other esm-only packages

Similar popularity